I've been having similar problems while calibrating my speakers. Again my situation is even pretty similar I'm using Axiom M3Tis (http://www.axiomaudio.com/m3ti_main.html#) as my mains and some crappy speakers that came with an old Aiwa shelf system rigged up as surrounds. All speakers are a direct 8 feet from the listening position and the room is rather small (11'x18'x8', WxLxH, with the listening postion along the longer wall). Still it requires that I pump the speakers up to +9dB or +10dB to make 75dB at reference level on a properly set SPL meter. Using DVE my mains fall about a dB or so short. This tends to be same whether I'm using DVE (connected over the digital coax input) or with the internal test tones although the internal tones tend to be just a few dB higher.